The Impact of Nocturia on Mortality: A Systematic Review and Meta-Analysis

Purpose: Nocturia (waking from sleep at night to void) is a common cause of sleep disruption associated with increased comorbidity and impaired quality of life. However, its impact on mortality remains unclear. We performed a systematic review and meta-analysis to evaluate the association of nocturia with mortality as a prognostic factor and a causal risk factor. Materials and Methods: We searched PubMed (R), Scopus (R), CINAHL (R) (Cumulative Index of Nursing and Allied Health Literature) and major conference abstracts up to December 31, 2018. Random effects meta-analyses were done to address the adjusted RR of mortality in people with nocturia. Metaregression was performed to explore potential determinants of heterogeneity, including the risk of bias. We applied the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) framework to rate the quality of evidence for nocturia as a prognostic risk factor for mortality and separately as a cause of mortality. Results: Of the 5,230 identified reports 11 observational studies proved eligible for inclusion. To assess nocturia 10 studies used symptom questionnaires and 1 used frequency-volume charts. Nocturia was defined as 2 or more episodes per night in 6 studies (55%) and as 3 or more episodes per night in 5 (45%). Pooled estimates demonstrated a RR of 1.27 (95% CI 1.16-1.40, I-2=48%) with an absolute 1.6% and 4.0% 5-year mortality difference in individuals 60 and 75 years old, respectively. The pooled estimates of relative risk did not differ significantly across varying age, gender, followup, nocturia case definition, risk of bias or study region. We rated the quality of evidence for nocturia as a prognostic factor as moderate and as a cause of mortality as very low. Conclusions: Nocturia is probably associated with an approximately 1.3-fold increased risk of death.